<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>计数器</title>
	</head>
	
	<body>
		<div id="app">
			<div class="input">
				<button @click="sub"> - </button>
				<span>{{num}}</span>
				<button @click="add"> + </button>
			</div>
		</div>
		<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
		<script> 
		var app = new Vue({
			el:"#app",
			data:{
				num:1
			},
			methods:{
				add:function(){
					if(this.num<10){
						this.num++;
					}else{
						alert("最大了");
					}
				},
				sub:function(){
					if(this.num>0){
						this.num--;
					}else{
						alert("最小了");
					}
				}
			}
		})
		</script>
	</body>
	
</html>